Techniques of applying polymer compounds having cationic groups and anionic groups to detergent compositions for automatic dishwashing machines have already been known, and WO-A 99/58633, WO-A 02/20709, EP-A 0998548, JP-A 2003-505535 and JP-A 2005-527686 can serve as references.
In recent years, automatic dishwashing machines are rapidly becoming widespread, and from the viewpoint of energy saving and resource saving, washing machines for reducing the amount of washing water used and for increasing the amount of tableware washed once have became mainstream. However, when tableware with much dirt is washed with such dishwashing machines, there is a problem of frequent occurrence of white deposited matter known as water spots on tableware after washing/drying, and there is strong demand for solving this problem.
As the technique of detergents for suppressing formation of such water spots, a technique of applying a cationic polymer compound or an amphoteric polymer compound is disclosed in WO-A 99/58633. There are also disclosed techniques of applying a cationic polymer compound or an amphoteric polymer compound as an inhibitor of formation of phosphate scales in WO-A 02/20709 and as a fading or corrosion inhibitor in EP-A 0998548. JP-A 2003-505535 and JP-A 2005-527686 disclose respectively techniques of a copolymer consisting of a diallylammonium monomer, a monomer having an acidic functional group and another monomer as an antiredeposition agent, and particularly JP-A 2005-527686 supra describes a detergent for machine-washing of kitchen goods and tableware, which is compounded with a solid, preliminarily compounded product containing said polymer adsorbed on, and/or absorbed to, a water-soluble inorganic carrier.